The United States has given preliminary approval for the sale of a Terminal High Altitude Area Defense (THAAD) missile defense system to Saudi Arabia with a price tag of $15 billion, according to reports and a statement by the U.S. Defense Security Cooperation Agency (DSCA).

The announcement, made on the heels of Saudi Arabia’s King Salman visit to U.S. rival Russia, includes the approval to sell 44 THAAD launchers and 360 missiles, as well as fire control stations and radars.

Congress has 30 days to consider the deal.

The DSCA said the sale “will support the foreign policy and national security objectives of the United States by improving the security of a friendly country. This sale furthers U.S. national security and foreign policy interests, and supports the long-term security of Saudi Arabia and the Gulf region in the face of Iranian and other regional threats. This potential sale will substantially increase Saudi Arabia’s capability to defend itself against the growing ballistic missile threat in the region.”

Also included are THAAD Battery maintenance equipment, 43 prime movers (trucks), generators, electrical power units, trailers, communications equipment, tools, test and maintenance equipment, repair and return, system integration and checkout, spare/repair parts, publications and technical documentation, personnel training and training equipment, U.S. Government and contractor technical and logistics personnel support services, facilities construction, studies, and other related elements of logistics and program support.

The United States deployed THAAD to South Korea this year to guard against North Korea’s shorter-range missiles, and analysts say such a system is aimed at bolstering Saudi defense against the threat of regional rival, Iran.

“Should Riyadh be reassured that THAAD is forthcoming and the Saudis don’t have to doubt Washington’s willingness to provide anti-ballistic missile systems,” Ibish wrote, “the S-400 deal might have already served its purpose as an announcement and an option rather than a reality.”